Background
A low perioperative serum potassium level (<4 mEq/l) and high blood glucose level (>200 mg/dl) during cardiac surgery is a preventable cause of high morbidity and mortality. In this study, we measured the changes in intraoperative levels of serum potassium and blood glucose in adult patients undergoing elective off-pump coronary artery bypass (OPCAB) surgery, while administering insulin intraoperatively as per the present guidelines.
Patients and methods
Thirty-six adults, aged 18–65 years, undergoing elective OPCAB surgery were enrolled in this study. Arterial blood gas analysis was performed at predetermined intraoperative time points to measure serum potassium and blood glucose levels as primary variables. Base excess, pH, and HCO were recorded as secondary variables. Insulin infusion was started according to the sliding scale, whenever blood glucose was more than 180 mg/dl. Intravenous potassium was supplemented, when serum potassium was less than 4 mEq/l. Quantitative variables were compared with baseline using paired test and repeated measure analysis of variance was used for comparison across follow up.
Results
Potassium chloride had to be continuously administered intravenous to maintain serum potassium levels more than 4 mEq/l throughout OPCAB surgery. There was a highly significant (<0.001) increase in the intraoperative blood glucose level compared with the baseline throughout the OPCAB surgery.
Conclusion
Patients are prone to hypokalemia and hyperglycemia during OPCAB surgery, despite following the current guidelines. More studies are needed to formulate a better insulin infusion protocol for maintaining normoglycemia and guidelines need to be formulated for continuous intraoperative potassium infusion during OPCAB surgery.